Apparatus for producing crimped yarn



July 3, 1962 M. R. HELD APPARATUS FOR PRODUCING CRIMPED YARN Filed July 7. 1960 R. Z P

M y B assists Patented July 3, 19162 fine York

Filed duly 7, 1%0, Ser. No. 41,341 3 tllaims. (Cl. 57-34) This invention relates to apparatus for producing crirnped synthetic yarns which require two high twist-heat setting operations. It is especially applicable to the production of crimp ed synthetic yarn, in which the second heat treating of the yarn is not as drastic as the first such treatment. More particularly, the present invention re lates to a simplified apparatus for effecting two heat treatments of yarn in the highly twisted condition with but a single source of heat. The apparatus of this invention is especially well suited to the production of a crimped synthetic yarn having little or no torque.

While the apparatus of this invention will be described as it may be applied to the production of a no-torque crimped synthetic yarn, is to be understood that the apparatus is not limited to the production of such yarn,

but may be employed wherever a yarn being crimped must be subjected to separate false twisting and heat setting operations.

In the copending application of Marijan Baebler, Serial No. 620,957, filed November 7, 1956, there is disclosed a method of crimping a continuous filament synthetic yarn, which comprises subjecting the yarn to a first false twist in one direction and heat setting in the highly twisted state, and then subsequently subjecting the so twisted and heat set yarn to a false twist in the opposite direction and heat treating in the second stage of false twist at a temperature somewhat lower than that in the first heat setting stage. The result is a single end yarn with little or no torque, which does not require plying together with another yarn in order to compensate for the torque normally present in a conventional crimped synthetic yarn to produce a yarn product which is ready for knitting or other use.

According to Baebler, if desired during the second false twisting the yarn may be twisted to a lower number p of turns than in the first false twisting, and in the second heat setting the twisted yarn may be subjected to a lower setting temperature than in the first setting step. The result is a single end multi-filament yarn which may show no actual torque, but which upon subsequent wetting will exhibit a torque in the direction, either S or Z, of the twist given the yarn in the first false twistin step. On the other hand, the Baebler yarn may show an actual torque in the direction of the twist given the yarn by the second false twisting step, and in such case when this yarn is Wetted it Will develop a torque due to and in the direction of the twist of the first false twisting step. If this torque developed by wetting equals the actual torque of the second false twisting step, then the yarn is without substantial torque. If the torque developed on Wetting is greater than the actual torque of the second step, then the final yarn will have a torque in the direction of the first false twisting. If it is less than the torque of the second step, the resulting yarn will have a torque in the direction of the second step. The Baebler process is desirably so carried out that the yarn following wetting has substantially no torque.

By synthetic yarn I intend a polyamidic yarn such as from polyhexamethylene adipamide or epsilon-caprolactam, or a yarn formed of polyacrylic or polyester fibers. These yarns usually come on the market with relatively few turns per meter, for example, 0 to 80. In a simple crimping operation, such a yarn is highly twisted, as with a false twisting device, to between about 1000 and 6000 T./m. The yarn is set in highly twisted condition generally at a temperature between about and 250 C. The temperature of setting as well as the time to which the yarn is subjected to that temperature determines the extent or completeness of setting. Following setting the yarn in passing through a false twisting device is untwisted to its initial twist.

According to the prior art where the processing of a synthetic yarn requires two heat settings, different heat setting elements have been employed, with the result that considerably difiiculty is often experienced in maintaining a proper relationship between the temperatures of the separate heating elements. In some instances it is highly desirable that the heat settings be carried out at the same temperature. However, with separate heat setting elements it very often happens that a downward change in temperature in the first element, for example, coincides With an upward temperature change in a second. element, causing a substantial overall temperature differential between them which has an unfavorable influence upon the quality and uniformity of the yarn being treated.

The apparatus of this invention includes a single heat setting element, desirably maintained at a fixed temperature, which is employed to eifect the first and the second heat settings. The setting element is broadly a heated metal plate over which the yarn passes in direct contact. Where it is desired to subject the yarn to a somewhat l ss drastic heat treatment in the second heat setting, for example, means are provided, which in conjunction with the particular shape of the heated contact surface cause the yarn to contact only a portion of the heated surface, with the result that the yarn is not so completely set as in the first heat setting.

In the accompanying drawing there is illustrated in diagrammatic perspective a preferred embodiment of the apparatus of the present invention.

In its broadest aspect the present apparatus comprises yarn feeding means and yarn conveying means with a heatable contact surface disposed therebetween over which the yarn passes in contact with the heated surface. A first false twisting device is positioned intermediate the contact surface and the yarn conveying means. A second yarn conveying means and a yarn receiving device are so positioned that the yarn again passes over the heated contact surface and thence through a second false twisting device.

Referring now to the accompanying drawing for a more detailed description of a preferred embodiment of the present invention, which is particularly adapted to the production of a no-torque crimped single end synthetic multi-filament yarn, there is shown a supply device for a synthetic yarn '1 such as a bobbin 2. The yarn 1 travels from the bobbin through a brake mechanism 3, which may be the same or a device similar to that described in the application of Heinrich Enneking, Serial No. ,3 filed on even date herewith, and thence to a roller 4 of a double roller assembly. The yarn is wound around roller 4 several times by Way of a smaller auxiliary roller- 6. The rollers 4 and 5 constitute a yarn feeding means indicated generally at 7, which forms a yarn restraining point, referred to for convenience herein as the first such point. Roller 4 of the yarn feeding device 7 is driven by frictional contact with driven shaft 8. Between the yarn feeding device 7 and a yarn conveying device indicated generally at 9 there is provided a heatable contact surface 11 which is a highly polished, preferably non-corrosive metal surface mounted upon a plate 12, which is suitably heated as by electrical resistant means, not shown. The contact surface 11 is slightly arched or curved as shown in the drawing. In a preferred embodiment the arched metal contact surface is about 600 mm. long.

A first false twisting device 13 is provided between contact surface 11 and the yarn conveying device 9 as shown. It may be any one of a variety of such devices, preferably belt driven, and may be rotated in either 8 or 2 direction. The spindle of the false twist device is preferably disposed at a distance of about 200-300 mm. from the heated contact surface '11, so that the yarn leaving contact surface 11 passes through a relatively long air zone where it cools somewhat before it reaches the twisting device 13.

The yarn conveying device 9 comprises a roller 14,

I which is frictionally driven by means of driven shaft 16,

and a smaller auxiliary roller 17. The yarn from the first false twist device 13 is wound around rollers 1d-17 several times and is conducted thence to a second yarn conveying device indicated generally at 18, comprising a roller 19 and a larger roller 21. The yarn passes several times about the rollers 19 and 21 as shown. Roller 19 is an idler, as is adjacent small roller 6, which may be on the same shaft, as shown. Roller 21 is preferably on the same shaft as adjacent roller 4 and is driven along with roller 4.

From the roller 21 of the second conveying device 18 the yarn travels through an adjustable guide 22, preferably "of pig-tail design, which may be of the type illustrated in the aforementioned Enneking application. The yarn guide 22 may be mounted on the machine frame or upon the plate 12, as shown, and is so positioned as to guide the yarn 1 onto the heated contact surface 11 at a predetermined point, from which point the yarn firmly engages the contact surface over a given length, X. In order to control the intensity of the second heat treatment of the yarn the guide 22 is adustable so that it is possible to alter the length of the distance X. Depending upon the position of guide 22, the yarn during its second passage over surface 11 may contact all or only a portion of the length of the contact surface. When it contacts less than the entire length of such surface, the heat treatment imparted thereto is less drastic.

Following this passage over the heated contact surface 11 the yarn passes through the spindle of a second false twist device 23, which in the production of the no-torque yarn is rotated in the opposite direction to the first such device. The false twisting device 23 is also preferably belt driven and may most conveniently be driven by the same belt which drives the spindle of false twist device 13. From the false twister 23 the yarn passes to roller 24 of a yarn receiving means indicated at 27. It is turned several times about roller 2 and auxiliary roller 2.6 and thence from roller 24 to a yarn take-up device indicated generally at 28.

The yarn receiving device 27 is associated with conveying device 9 in the same manner as conveying device '18 is associated with yarn feeding device 7. These compound roller assemblies are preferably of the type illustrated in FIGS. 3, 7 and 8 of the aforementioned Enneking application.

As indicated above, the yarn feeding device 7 constitutes a first restraining point for the yarn. Yarn conveying means 9 also constitutes a restraining point, referred to as the second such point. This is necessary in order to prevent slippage of the yarn whichis undergoing false twisting by passage through false twist device 13. The highly twisted yarn between roller 4 and false twisting device 13 is thermally set by passage over heated contact surface 11 and subsequently untwisted between the first false twist device and roller 14 of yarn conveying device 9 to the initial twist of the yarn on the bobbin 2. Roller 4 is driven at a somewhat higher peripheral spee than roller 14. That is to say, the yarn is overfed to the false twist device 13. Similarly, the yarn leaves roller 21 of conveying device 18, which constitutes a third yarn restraining point, at a faster rate than it is received at roller 24 of receiving means 27, the fourth restraining point. Accordingly, it is necessary that the peripheral speed of the various rollers may be varied in relation to the peripheral speed of the next subsequent roller in the system and the degree of yarn overfeed or underfeed thus controlled. Feeding conditions are dependent upon the composition and physical condition of the yarn, and the effects desired in the finished yarn product.

In the production of a typical crim-ped 30 denier, 10 filament nylon yarn of very low torque, the yarn between feeding device 7 and the first false twister may be highly twisted approximately 4500 T./rn. S and the heated contact surface maintained at about 225 C. During the secind false twisting the yarn may be high twisted about 3000 T./m. Z, and the yarn guide 22 so adjusted that distance X over which the yarn passes in contact with heated surface 11 is approximately half the length of the surface 11.

In the embodiment specifically described only one yarn guide is provided, with such guide controlling the length of contact of the yarn with heated surface 11 during its second passage thereover. Obviously, without departing from the spirit of this invention another such guide might be provided to control the length of contact during the first passage of the yarn over the heated surface, should less than complete contact over the full length of heated surface 11 prove desirable during the first heat setting.

There has thus been outlined broadly the important features of the apparatus of thev present invention and a specific embodiment has been described in detail. Those skilled in the art will appreciate that the concept upon which this application is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is apparent therefore that the appended claims be regarded as including such equivalent means as do not depart from the spirit and scope of the invention.

I claim: x

1. Apparatus for crimping a synthetic yarn which comprises yarn feeding means, yarn conveying means, a heatable contact surface disposed therebetween for the passage of said yarn thereover, a first false twisting device intermediate said heatable contact surface and said yarn conveying means, a second yarn conveying means and a yarn receiving means so positioned that said yarn again passes over said contact surface, an adjustable yarn guide so positioned relative to the heatable contact surface as to control the length of yarn contacting the heatable contact surface during the second passage of the yarn thereover, and a second false twisting device positioned intermediate said contact surface and said yarn receiving means.

2. Apparatus as set forth in claim 1 wherein said yarn guide is positioned intermediate the second yarn conveying means and the heatable contact surface.

3. Apparatus for crimping synthetic yarn, comprising means for feeding yarn to be crimped constituting a first restraining point, yarn conveying means constituting a second restraining point, a heatable arched contact surface over which the yarn is adapted to pass in travellin between said restraining points, a false twisting devic between said-contact surface and the second restrainin point, a second yarn conveying means constituting a third References Cited in the file of this patent UNITED STATES PATENTS 2,624,934 Munson et a1 Jan. 13 2,864,229 Seem et a1 Dec. 16, 2,921,358 Cox et a1. Jan. 19,

FOREIGN PATENTS 203,619 Austria May 25, 219,270 Australia Dec. 5,

10 788,944 Great Britain Jan. 8, 807,516 Great Britain Jan. 14, 

